Known injection devices for injection of medicaments into a patient include traditional hypodermic needle syringes, needle-free jet injectors like the ones disclosed in U.S. Pat. Nos. 5,599,302; 5,062,830; and 4,790,824; needle-assisted injectors, such as those described in U.S. Patent Publication No. 2005/0033234; and self-injectors or autoinjectors like the ones disclosed in U.S. Pat. Nos. 4,553,962 and 4,378,015, and PCT Publications WO 95/29720 and WO 97/14455.
The liquid medicament preparations that are injected from such injection devices are also known to contain insoluble or particulate drug constituents. This can be due to the insolubility of the drug in the vehicle or medium in which it is stored. As a result, the insoluble or particulate drug constituents in the liquid preparations separate upon storage, even over short periods of time.
The particulates can potentially clog the needle, and this is particularly problematic in cases when the liquid pharmaceutical preparation containing insoluble particles is self-administered or administered in the home by non-professional care-givers. Ordinarily, when these liquid pharmaceutical preparations are administered in the hospital or other healthcare providing institutions by trained staff, one can rely on adequate handling of the medication to ensure proper drug delivery, despite settled material and plugged needles. However when such pharmaceutical preparations are self-administered or administered in the home by non-professional care-givers, the risk for inadequate handling of the medication increases since the injection of such formulations requires that the administrator be able to adequately resuspend any settled material and clear the needle to ensure proper drug delivery.
Thus, an injector is needed that can facilitate reliable combination of injectable components prior to injection.